microRNA-181a downregulates deptor for TGFß-induced glomerular mesangial cell hypertrophy and matrix protein expression.
Exp Cell Res
; 364(1): 5-15, 2018 03 01.
Article
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| MEDLINE
| ID: mdl-29397070
ABSTRACT
TGFß contributes to mesangial cell hypertrophy and matrix protein increase in various kidney diseases including diabetic nephropathy. Deptor is an mTOR-interacting protein and suppresses mTORC1 and mTORC2 activities. We have recently shown that TGFß-induced inhibition of deptor increases the mTOR activity. The mechanism by which TGFß regulates deptor expression is not known. Here we identify deptor as a target of the microRNA-181a. We show that in mesangial cells, TGFß increases the expression of miR-181a to downregulate deptor. Decrease in deptor augments mTORC2 activity, resulting in phosphorylation/activation of Akt kinase. Akt promotes inactivating phosphorylation of PRAS40 and tuberin, leading to stimulation of mTORC1. miR-181a-mimic increased mTORC1 and C2 activities, while anti-miR-181a inhibited them. mTORC1 controls protein synthesis via phosphorylation of translation initiation and elongation suppressors 4EBP-1 and eEF2 kinase. TGFß-stimulated miR-181a increased the phosphorylation of 4EBP-1 and eEF2 kinase, resulting in their inactivation. miR-181a-dependent inactivation of eEF2 kinase caused dephosphorylation of eEF2. Consequently, miR-181a-mimic increased protein synthesis and hypertrophy of mesangial cells similar to TGFß. Anti-miR-181a blocked these events in a deptor-dependent manner. Finally, TGFß-miR-181a-driven deptor downregulation increased the expression of fibronectin. Our results identify a novel mechanism involving miR-181a-driven deptor downregulation, which contributes to mesangial cell pathologies in renal complications.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Regulación de la Expresión Génica
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Fibronectinas
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MicroARNs
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Péptidos y Proteínas de Señalización Intracelular
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Células Mesangiales
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Factor de Crecimiento Transformador beta1
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Hipertrofia
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Glomérulos Renales
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Exp Cell Res
Año:
2018
Tipo del documento:
Article
País de afiliación:
Estados Unidos